Salient features of a parallel programmable interface-8255, Computer Engineering

Assignment Help:

Determine the salient features of a parallel programmable interface, 8255.

  • 24 I/O lines in 3 8-bit port groups - A, B, C
  • A, B can be 8-bit input or output ports
  • C can serve as 2 4-bit input or output ports
  • 3 modes of operation:

- Mode 0: A, B, C simple input or output level sensitive ports

- Mode 1: A, B input or output ports with strobe control in C

- Mode 2: A is bidirectional with control/handshake in B and C

  • A, B can only change 1 byte at a time
  • C has individual bit set/reset capability
  • Advantage is non-dedicated circuit can change port configuration with software and no 'glue logic'
  • Ports A, B, and C are used for I/O data.
  • The control register is programmed to select the operation mode of the three ports A, B, and C.
  • Mode0: simple I/O mode
  • Any of the ports A, B, CL and CU can be programmed as input or output.
  • No control of individual bits (all bits are out or all bits are in)
  • Mode 1: Ports A and B can be used as input or output ports with handshaking.
  • Mode2: Port A can be used as bidirectional I/O port with handshaking

 


Related Discussions:- Salient features of a parallel programmable interface-8255

Explain ones complement operator, One's Complement Operator: ~ The one'...

One's Complement Operator: ~ The one's complement operator, sometimes called the "bitwise complement" or "bitwise NOT" operator, produces the bitwise one's complement of its op

Explain implementation techniques, Explain Implementation techniques Im...

Explain Implementation techniques Implementation techniques(e.g. remote invocation, HTTP). An event-based cooperation can be executed using message passing or it can  be based

Sorting algorithms, Two way merge sort for 84,83,78,90,23,123,98,159,8,200

Two way merge sort for 84,83,78,90,23,123,98,159,8,200

Define arithmetic pipelines, Arithmetic Pipelines The technique of pipe...

Arithmetic Pipelines The technique of pipelining can be applied to various complex and low arithmetic operations to speed up processing time. Pipelines used for arithmetic calc

Implementation of a simple arithmetic, Q. Implementation of a Simple Arithm...

Q. Implementation of a Simple Arithmetic? So, by now we have concerned how logic and arithmetic micro-operations can be applied individually. If we combine these 2 circuits alo

Xml can play when dynamically generating html pages , Explain the role that...

Explain the role that XML can play when dynamically generating HTML pages from a relational database? Ans) Even if student has never participated in a project involving this typ

Challenges in changing information technology, Q: Challenges and Prospects ...

Q: Challenges and Prospects in Changing Information Technology? There is no doubt that information technology has made significant progress during the past two decades. Modern

Phase - thermodynamics, Phase - Thermodynamics: A phase is quantity of...

Phase - Thermodynamics: A phase is quantity of matter that is homogeneous throughout in chemical composition and physical structure. If the matter is all gas, all liquid or

What is the significance of the memory table ''screen'', What is the signif...

What is the significance of the memory table 'SCREEN'? At runtime, attributes for every screen field are stored in the memory table called 'SCREEN'.  We need not declare this

Difference among the static rams and dynamic ram, Difference among the Stat...

Difference among the Static rams and dynamic rams. Static RAM: It is costly as each bit of memory will take around 6 CMOS transistors. More speedy as transistors are us

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd